Liquid and gaseous fuel production from solar energy

ABSTRACT

A system for and method of conversion of electrical energy into gaseous and liquid fuels, comprising steps of and means for provide a hydrocarbon fuels, including a collector for collecting carbon dioxide gas from a carbon dioxide gas source, a means for reducing at least a portion of the collected carbon dioxide gas to carbon monoxide, a means for producing hydrogen from a hydrogen source and a vessel for thermo-chemically reacting the hydrogen gas with carbon dioxide in a Fischer-Tropsch type process in the presence of a catalyst and heat.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a non-provisional of Provisional Application No. 61/009,474filed on Dec. 29, 2007 and is a continuation in part of 12/053,279 filedMar. 21, 2008, which claims domestic priority to U.S. Provisional PatentApplication Ser. No. 60/921,030 filed on Mar. 31, 2007, and pending U.S.Non-provisional application Ser. No. 11/209,161, filed on Aug. 22, 2005and also is a continuation in part of U.S. patent application Ser. No.11/644,693, filed Dec. 12, 2006 now abandoned, which is anon-provisional of Provisional Application No. 60/845,129, filed on Sep.16, 2006 and of Provisional Application No. 60/854,278, filed on Oct.25, 2006, all of which applications are incorporated by reference as iffully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to devices that convert solar and/orwaste heat energy to electricity, the electricity in turn being used inan electrolysis process to make hydrogen gas from water, which hydrogenthen in turn is used to make gaseous and liquid fuels via the reactionof hydrogen gas with CO₂ gas when exposed to the presence of heat,temperature and/or catalytic materials. More specifically, it relates todevices that use metal hydride heat engine technology to convert thesolar and/or waste heat energy into electrical energy which in turn isused to make Hydrogen gas via the electrolysis of water, which then inturn is used to make gaseous and liquid fuels via the reaction of thehydrogen gas with CO₂ gas when exposed to the presence of catalyticmaterials and/or heat and temperature.

2. Background Art

Thermal hydrogen compressors for a broad range of applications have beenknown for over twenty years. Thermal compression of hydrogen usingreversible metal hydride alloys offers an economical alternative totraditional mechanical hydrogen compressors. Hydride compressors arecompact, silent, do not require dynamic seals or excessive maintenanceand can operate unattended for long periods. When powered by “waste”heat, total energy consumption is only a fraction of that required formechanical compression, which reduces the cost of hydrogen productionand increases energy use efficiency. The simplicity and passiveoperation of the thermal compression process offer many advantages overmechanical compressors. Hydrogen compressors of this type are describedin U.S. Pat. No. 4,282,931 and commonly owned U.S. Pat. Nos. 4,402,187;4,505,120; 5,450,721; 4,781,246; 4,884,953; 5,623,987 and 6,508,866, thedisclosures of which are all incorporated by reference herein, asappropriate.

The common thread in all of the heretofore known hydride compressortechnologies is the use of metal hydrides to absorb and release hydrogenat predesignated appropriate times in the hydriding/de-hydriding cycleso as to compress the hydrogen to ever higher pressures. Hydrogenpressure in a metal hydride is known to increase exponentially withincreasing temperature. The pressure rise generated in a single stagehydride heat exchanger may be as high as 300%. Although theoreticalpressure increase is calculated to be as much as 500%, naturalinefficiencies, such as heat transfer resistance and hydrogen pressuredrop, tend to reduce the increase in actual practice.

The high pressure hydrogen gas generated by the hydride compressor canbe expanded through a turbine/electric generator type of device toproduce shaft power and electric power. Electric power plants arecapable of converting the high-pressure steam or water pressure createdin a generator at a dam into electricity. Other methods, for example,direct solar to electricity conversion in solar panel or battery power,can be used to generate an initial amount of electricity to run anelectrolyzer for converting water into oxygen and more importantlyhydrogen in an electrolysis process resulting in the production of andoxygen gas. The hydrogen is then used in further processing, as will beexplained below in further detail.

When a repeating cycle of hydrogen absorption and desorption is used ina heat exchange cycle, as in, for example, aforementioned U.S. Pat. Nos.5,450,721, and 5,623,987 and in U.S. Published Application No.2005/0274138, hydrogen absorption in a metal hydride alloy as used inheat exchange units is known to be accompanied by a heat of formationwhich is exothermic. In order to continuously absorb hydrogen to analloy's maximum capacity, heat must be removed from the bed at anappropriate stage in the cycle. The rate at which a hydride alloy canabsorb or release hydrogen is dependent upon the rate at which heat canbe transferred into or out of the alloy. Increasing the heat transferrate will allow the processing of higher flow rates, or alternatively,the same flow rate can be processed by proportionately smaller amountsof alloy. Therefore, small containers capable of rapid heat transfer canhandle high flow rates. Alternatively, containers having high surface tovolume ratios, such as those described in aforementioned U.S. Pat. No.5,623,987, may be utilized to simultaneously provide rapid heat andhydrogen transfer through the system.

More recently, photovoltaic technology has long been known to convertsolar energy directly into electricity. In ongoing research, governmentagencies, laboratories and private companies endeavor to make thistechnology commercially viable and historically have met with limitedsuccess. These efforts are taking on new urgency and are expected tomultiply in view of the world's appetite for energy and depletion ofnatural gas and petroleum resources. The search for such alternativeenergy production has also become critical in view of the need to reducecarbon emissions so as to protect the worldwide environment from climatechange due to a general warming of the world's troposphere.

Using the electricity produced by solar photovoltaics in an electrolyzerto produce Hydrogen gas is also well known. However, a unitary system orprocess wherein hydrogen derived from electrolysis and then reacting itwith carbon dioxide to make gaseous and liquid fuels has not yet beenposited, despite recognized promise to remove carbon from the atmosphereand the production of fuels without utilizing carbon emission fuels fromthe ground.

SUMMARY OF THE INVENTION

The economic utilization of solar thermal for electric power generationhas long been recognized as a possible solution to the world's quest foran alternative form of energy. Several characteristics of solar energyprovide unparalleled features that make solar power desirable as anenergy source. Besides being the primary and ultimate source of mostforms of naturally occurring energy used as a matter of course, solarand thermal energy is freely available in most areas of the world on ayear round basis, is abundant, has economic efficiency and lacks mostdetrimental environmental effects, such as pollution and green houseemissions and other harmful effects to the environment. Energy expertshave opined that solar energy has the potential to easily supply all ofthe world's energy needs in manner that minimizes the harmful effects ofenvironmental damage and is locally produced so that the economy is notimpacted.

The use of a hydride heat engine to convert the thermal energy in solarand/or waste heat into electricity was the subject of non-provisionalU.S. patent application Ser. No. 11/644,693 filed on Dec. 12, 2006.Electric power from a heat engine made according to the aforementioned'693 application and using it to electrolyze water to make hydrogen andoxygen gas, and then completing the reaction of the hydrogen gas with anappropriate amount of Carbon Dioxide to make gaseous and liquid fuelsvia the use of Fischer-Tropsch processes in a single unified system isnot available in the prior art.

Heat engine and photovoltaic technology has long been known to convertsolar energy directly into electricity. Currently, many companiesendeavor to make this technology commercially viable. Other processesuse, for example, the high pressure hydrogen developed in the processaccording to the aforementioned '693 application, also assigned to theassignee of this invention and described therein utilizes the method toproduce electricity solely form solar energy, or waste heat.

In addition, the process of using electricity produced by heat enginesand solar photovoltaic cells to produce Hydrogen gas in an electrolyzeris also well known. In effect, the solar powered electrical source isutilized to power an electrolysis mechanism that separates water intoits constituent hydrogen and oxygen atoms and then collects the gas forfurther processing. The efficiency is increased in respect of the systemif the power comes from a photovoltaic or other solar powered source,but this is not crucial to the structure and operation of the presentinvention.

The F-T process of using metal and/or metal oxide catalysts in thepresence of heat and temperature to convert gaseous, liquid and solidfuels, such as methane, petroleum oil and coal, into Hydrogen and CarbonMonoxide gas, and then into different forms of gaseous and liquid fuelsis well known and was first reduced to production type quantities in the1940s by Germany during WWII. This process is now known world-wide asthe “Fischer-Tropsch” process.

Extraction of Carbon Dioxide from the surrounding ambient air viahydride refrigeration techniques or by using other suitable processes.For example, carbon dioxide may be obtained by conventional chemicalreactions processes, and even more efficiently, may be obtained byutilizing waste carbon dioxide that has been recaptured in carbon sinkprocesses that are being implemented to recapture carbon byproductsbefore they are emitted into the atmosphere.

After the carbon dioxide has been isolated, it is reacted it with thehydrogen gas that itself may be generated by the solar powered heatengine and/or photovoltaic means, the reaction proceeding in a variationof the Fischer-Tropsch process, that will result in the economicproduction of gaseous and liquid type fuels. Modification of the classicF-T process is required because the staring material is carbon dioxide,rather than carbon monoxide, but the removal of an oxygen atom, fromcarbon dioxide is a known process.

The present invention combines known technologies from the field ofcarbon dioxide production and from carbon chain building which incombination have produced a new invention comprising a solar or thermalpowered reaction process which can generate gaseous or liquid fuels.Moreover, if the carbon dioxide gas has been generated by extracting itfrom the ambient air by following the methods of the invention so as toreduce the carbon dioxide as a greenhouse gas, then the gaseous andliquid fuels produced by these processes can truly be considered carbonneutral.

To provide for the necessary teaching of the invention, there is taughtand claimed herein a method of conversion of electrical energy intogaseous and liquid fuels, comprising collecting carbon dioxide gas froma carbon dioxide gas source, reducing at least a portion of thecollected carbon dioxide gas to carbon monoxide, producing hydrogen froma hydrogen source, thermo-chemically reacting the hydrogen gas withcarbon dioxide in a Fischer-Tropsch process to produce gaseous andliquid fuels. In a further modification of the process, the hydrocarbonproducts of the Fischer-Tropsch process may be further processed toproduce solid type fuels, such as waxes, tars and other solidcarbon-hydrogen “fuels” that can permanently sequester the carbon theycontain.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be discussed in further detail below withreference to the accompanying figures in which:

FIG. 1 is a schematic diagram view of a hydrogen compressor utilizing asolar thermal energy source according to the present invention;

FIGS. 2A and 2B represent schematic diagrams of a simplified hydrogencompressor mechanism according to the present invention showing thetwo-step process for increasing the pressure of hydrogen gas in thecompressor chamber;

FIG. 3 is a schematic diagram of a high-pressure hydrogen compressoraccording to the present invention utilizing successive pluralmechanisms as shown in FIGS. 2A and 2B;

FIG. 4 illustrates in a schematic diagram the configuration of a thermalhydrogen compressor utilizing the hydrogen pressurizing system shown inFIG. 1 to produce high-pressure hydrogen according to this invention;

FIG. 5 is a detailed schematic diagram of the hydraulic motor generatormechanism according to the present invention, for providing electricityutilizing a high-pressure gas source;

FIG. 6 is detail view of the solar collector isolated from the systemshown in FIG. 1;

FIG. 7 is a process flow diagram illustrating the method steps of aconversion of solar energy into gaseous and liquid type fuels via theFischer-Tropsch process;

FIG. 8 is a schematic view of a process flow diagram in which theprecursors of the modified Fischer-Tropsch process uses solar energy toeconomically extract carbon dioxide from the ambient air via ahydride/hydrogen liquefaction process; and

The drawing figures are submitted for purposes of illustration of thepreferred embodiments only and are not to be considered limiting of theinvention as described below and claimed in the following claims.

A detailed description of the preferred embodiments follows.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, a multi-stage heat exchange system 10 accordingto the present invention is illustrated showing in schematic outline theelements of the system, with heat being provided in the form ofradiation form the sun. The multi-stage heat exchange system 10comprises a solar hot water panel heat collector 12, which may beconventional, as shown. Alternatively, the collector may havecharacteristics that will enhance the energy collection efficiency orconcentration, for example, such as that provided by solar energycollectors shown and described in U.S. Pat. No. 4,002,499 to Winston, aswell as others.

The collector may comprise a simple array of pipes 17, 18, atransitional portion of which is embedded in a black, or solar energyabsorbing, matrix 19, such as those used in conventional solar waterheaters. A heat transfer fluid inflow pipe 17 permits water, or anotherheat transfer material, to flow into the solar collector 12 through apipe manifold 14, as shown, where the water is heated by the solarenergy collected in the collector 12. The water or heat transfer mediumthen flows out as hot water, at a temperature of about 85-95° F.,through a second pipe 18 connected to a manifold 15 at the opposite, orhot, end of the solar collector 12. Pipe 18 is itself in fluidcommunication with a hydride bed array 60, as will be described ingreater detail below with reference to the description of FIG. 4 below.

A source of cold water may also be provided through a second series ofpipes 20, 22 that are in fluid communication with the hydride bed array60, to provide for a cold source to drive the hydrogen pressurizationprocess. The pipes 20, 22 comprising the cold water loop may alsoprovide for cooling of the fluid heat transfer medium, for example,water, by passing the fluid through an optional cooling fan device 28 orother type of cooling arrangement. Alternatively, the cold water may beobtained from a municipal tap, and after performing its cooling functionin the hydride bed array 60, it may be vented to the environment ordirected to a drain (not shown). Pumps providing for heat transfer ofthe fluid medium, for example pumps 24, 26, may be utilized for fluidcirculation of the hot and cold heat transfer medium through the closedloop system of either the hot or cold heat transfer medium pipes 17, 18or 20, 22, respectively. Additionally, a fan cooler 28 in line with thepipe 17 may be utilized to cool off the water or other heat transfermedium that is used on the “cold” side of the multi-stage compressor, aswill be described in greater detail with reference to FIG. 4, below.

While the elements of the system 10 are shown schematically in FIG. 1,those having ordinary skill in the art will understand the properconfiguration of such a continuous loop system. For example, the hotwater outflow pipe 18 may include an insulating wrap around it tomaintain the water temperature as high as possible during the transportto the “hot” hydride chambers in hydride bed array 62 (FIG. 4) disposedwithin the multistage hydride compressor 60. Insulation would assuredlybe required for a system where the solar energy is concentrated, asdescribed in aforementioned U.S. Pat. No. 4,002,499, and special pipingand heat transfer fluid would also be required, since the temperaturesachieved by such a solar energy concentrator may exceed 600° F.

Referring again to FIG. 1, the high pressure hydrogen gas generated bythe hydride bed array 62 within the multistage hydride compressor 60 isin fluid communication with a hydraulic motor generator 30 throughhydrogen gas pipes 32, 34, as shown. A high pressure pipe 32 provideshydrogen at ultra high pressures to the hydraulic motor generator 30, asis described in greater detail below with reference to FIG. 4, and areturn pipe 34 returns the depressurized hydrogen gas to the multi-stagepressurization thermal compressor 60, as shown. The high pressurehydrogen gas may be controlled by valves, two valves 46, 48 of which areshown, to provide the driving impetus to the hydraulic motor generator30, described in greater detail with reference to the generator 30illustrated in FIG. 5 below. As shown in FIG. 1, the resulting energyproduced by the system may be in the form of electrical power outputthrough a set of lead wires 50, 52. Referring now to FIGS. 2A and 2B, ahydride chamber 62A or 62B (FIG. 4) is shown that may be in fluidcommunication with an opposite one of the chambers 62A, 62B, so thatwhen one chamber, for example, 62A, is attracting the inflow of hydrogengas because of the cold water to which it is exposed, the other end ofthe dual chamber arrangement, for example, 62B is degassing the hydrogenbecause it is exposed to a hot water pipes 14, 20 (FIG. 1), as shownschematically in FIGS. 2A and 2B.

Referring now to FIG. 3, successive hydride beds are shown as an exampleof how providing hydride alloys capable of absorbing hydrogen atdiffering temperatures to provide staged or stepped increases in thehydrogen pressure may be utilized to exponentially multiply the pressureof the hydrogen gas in the multi stage thermal compressor arrangement60. By successively running cold and hot water to pipes that are incontact with the different hydride alloy materials in each of thechambers 62A 1-5, while maintaining the appropriate condition of thevalves 180, 182, 184, 186 disposed in line between the chambers, so thatthe hydrogen is thermally pumped against the pressure to build itspressure up. As shown in the example in FIG. 3, the pressure can beincreased from 21 psia to about 5100 psia when the hydrogen is absorbedand desorbed in five successive stages, with a three fold pressureincrease between successive stages, with a temperature differentialbetween the hot and cold water being less than 100° F.

The multi-stage hydrogen gas thermal compressor 60 is shown in greaterschematic detail in FIG. 4. The improvements provide a number ofbenefits, which include not only the compression of hydrogen gas, forexample, by a tenfold increase in hydrogen gas pressure at eachsuccessive stage. Additional benefits derive from utilizing theinvention described and claimed herein, resulting in more efficient,less expensive operation for providing an economical and commerciallyviable source of energy, for example, electrical energy, that isobtained by use of the hydrogen gas pressurized at ultra high pressuresthat may be used to drive, a turbine or hydraulic motor generator 30 aswill be described below.

Referring now to FIG. 4, a hydrogen compressor system 60 according tothe present invention, the structure of an inventive hydrogen gascompressor, utilizing the present invention, is described relative toits principles of operation. A thermal compressor system 60, as shown inFIG. 2, comprises three essential subsystems. A first subsystemcomprises at least two sets of hydride beds, an A set, namely 62A, 64A,66A, 68A and 70A, and a B set, namely 62B, 64B, 66B, 68B and 70B,including piping between them, as will be described below. Anotheressential subsystem is the hot and cold water circulation subsystems 72,74, and the control subsystem CPU (not shown). Each of these knownsubsystems will be briefly described, but for a fuller, more elaboratedescription of the hydride heat exchange units, reference is made to theteaching of the aforementioned U.S. Pat. Nos. 4,402,187 and 4,505,120.

Each similarly numbered hydride bed pair, for example, hydride bedcontainers 62A, 62B and connecting pipes 82A, 82B comprise a heatexchange unit 62; and similarly the remaining hydride bed containerpairs 64A, 64B together with pipes 84A, 84B comprise a second hydrideheat exchange unit, and so on. The piping 82A, 82B, 84A, 84B etc. isinterconnected, as will be described below. The first set of pipes 82A,82B is connected to the hydrogen inlet by means of the internal inletpipe 116. Inlet pipe 116 has disposed along it a low pressure switch 100and a safety pressure, relief valve 102. The low pressure switch 100will close off the inlet if pressure goes below a certain value, i.e.,15 p.s.i., and the pressure relief switch 102 will release incominghydrogen gas if it exceeds a predetermined pressure value, e.g. 200p.s.i.a. These values may be adjusted for uses in generating the highpressures according to the present invention, however, or the structuresmay be provided for use in high-pressure environments without anoverpressure venting feature. Exposure of the piping 16, 116 topressures below atmospheric pressure are to be avoided in that anegative pressure will lead to undesirably attract gaseous impuritiesfrom the ambient environment into the system 60. Likewise, if for someaccidental reason the hydrogen gas pressure within the inlet pipeexceeds a safe or expected pressure, the pressure relieve valve willvent the hydrogen to a vent stack for the processing, as will bedescribed below.

Further along the inlet pipe 116, there is disposed a hydrogen cut offvalve 104 such as a solenoid valve, which is controlled by the CPUthrough electrical control connections (not shown). The valve 104 opensand closes in accordance with the cycle timing of the remainder of thecompressor arrangement 60 to introduce hydrogen gas into the system forcompression, as needed. Of course, in a closed system, for example, suchas that shown in FIG. 1, no hydrogen gas would be vented and there wouldbe no need for adding any hydrogen to the system for further processing.

Thermal compressors provide great benefits, as they are typically aboutone tenth the mass of and smaller than conventional mechanicalcompressors sized to the same hydrogen flow rates and compressionratios. For example, a thermal compressor designed to compress hydrogenfrom 100 psia to 5,000 psia (CR=50), with a hydrogen flow rate of 1,000SCFH, will have a total compressor mass of about 115 kg, while the massof an equivalent mechanical compressor is over 1,300 kg. Thermalcompressors with hydrogen compression ratios greater than 1,000 andhydrogen flow rates greater than 10,000 SCFH can be provided on a custombasis.

FIG. 4 shows as an alternative embodiment of a thermal powered hydrideheat compressor for increasing the pressure as an example of a hydridealloy absorbing hydrogen at 565 psia pressure when at 25° C. anddischarging hydrogen at 1,700 psia when heated to 75° C. The descriptionof the hydrogen compressor system 60 is mostly conventional. Within eachof the piping 82A, 82B, each connected to the inlet pipe 116, is aone-way check valve 106, which opens only when the hydrogen gas pressureon the side of inlet pipe 116 is greater than that of the piping 82A,82B. Thus, as the hydrogen is delivered downstream, i.e., from heatexchange unit 62 toward unit 64 and on wards, the pressure of thehydrogen within the first heat exchange unit 62 will fall below thenormal gas pressure present in the inlet pipe 116. For the most part,each hydride bed pair 64A, 64B; 66A, 66B; 68A, 68B, etc. has as ahydrogen source the immediately adjacent upstream bed, and a connectionprovided by, for example, hydrogen inlet pipes 82A, 82B; 84A, 84B; etc.The inlet pipes 82A, 82B provide a path for the hydrogen 85 to thehydride bed within each of the containers, 64A, 64B, 66A, 66B, etc. Asthe cold water and hot water are cycled from one series of beds, e.g.,from the A series to the B series, the hydrogen is compressed at eachstage until it reaches the internal outlet pipe 118, connected to outletpipe 18 (FIG. 1). The process of hydrogen gas compression is describedin aforementioned U.S. Pat. Nos. 4,402,187 and 4,505,120, incorporatedby reference, and review of those patents and others set forth above isrecommended for a more detailed description.

An optional feature utilizable in the embodiment of hydrogen compressor60 shown in FIG. 2 is a hydrogen 108 vent, the opening and closing ofwhich is controlled by the CPU (not shown), through an electricalconnection 110 extending therebetween. The timing of the opening andclosing of hydrogen vents 108 is most conveniently and efficiently doneduring the periods immediately prior to the switchover of the hot andcold water streams, that is, at the time that the bed which was incontact with the cold water is switched to hot water. At this time, thehydrogen absorption/desorption occurring in the first two metal hydridebeds 62A, 62B, approaches equilibrium, and so that the hydrogen pressureof the pipes 82A, 82B is not at a maximum.

Venting is directed by the controller CPU as it receives a signal of thepressure differential within the piping 82A, 82B. The CPU signals thehydrogen vent 108, which is opened for at most one to two seconds. Anyimpurities entrained within the hydrogen gas, pressurized at about 30-40p.s.i., are ejected into the exit vent pipe 114, which connects to acentral vent stack 120. The vent stack itself may be connected to adisposal site for the “impulse” hydrogen gas, where it may be burnedoff, for example, in a hot water heater for providing otherwise wasteheat for the useful purpose of heating the hot water utilized in thecompressor 60.

In the period when the maximum hydrogen is absorbed in the metal hydridebeds 62A, 62B, the hydrogen therein is almost pure, whereas the hydrogenin the piping 82A, 82B is relatively impure. Makeup hydrogen isavailable from the source, and in expelling the “impure” hydrogen gasduring each throughput cycle, a larger relative proportion of theimpurity gases is expelled than of the hydrogen gas within the system.That is, after the vents 108 are closed and the hydrogen gas isdesorbed, the remaining hydrogen in pipes 82A, 82B includes fewerimpurities than before the venting process because the makeup hydrogenin the next aliquot received from the source 14 will have relativelyless impurities than the hydrogen gas vented through vents 108. Theventing process may be utilized during every cycle, or V₂ cycle, so thatif desired, impurity gases will not build up in the system therebyavoiding ultimate saturation of the desiccant material.

For example, vents (not shown) may be inserted in pipes 84A, 84B, andmay be controlled by a central processing unit (not shown) to vent asecond aliquot of hydrogen gas that may have included some minor levelof impurities. The vented hydrogen gas does not necessarily translateinto waste, however, because of the transformation of hydrogen gas thatmay have impurities to a pure hydrogen gas stream, which is morevaluable commercially than wet or impure hydrogen. Moreover, burning ofvented hydrogen in a stack to heat water that can be used to furtherpressurize the hydrogen in the compressor arrangement 60 or for otheruse, for example, to produce fuel savings and provide a self-generatingenergy source to the system.

In the thermal compressor 60, hydrogen gas is absorbed in a reversiblemetal hydride alloy in the hydride bed 62A at low pressure in awater-cooled container. The container is subsequently heated with hotwater, which releases the hydrogen gas at a higher pressure. Continuouscompression is achieved with two identical containers in a parallelconfiguration; one container cooled by water absorbs hydrogen while theother is heated with hot water to release hydrogen at the same rate. Thecool and hot water streams in pipes are periodically switched by ballvalve switches 78 so that water flowing through one set of pipes 77switches to the other set of pipes 79, and vice versa and the simplecheck valves 106 keep hydrogen gas moving through the compressor. In asecond embodiment, hydrogen gas purification is a feature which may beused in any of a number of applications, such as ring manifold type heatexchangers, as described in aforementioned U.S. Pat. No. 5,623,987, inair conditioners utilizing metal hydrides, described in U.S. Pat. No.5,450,721, and in other heat exchange devices, such as described in U.S.Pat. No. 4,781,246, used in refrigerators, heat pumps, and low pressurehydrogen storage devices. Referring now to FIG. 5, the hydraulic motorassembly 30 shown in FIG. 1 is described in greater detail. Twohydraulic chambers 200 and 202 are driven by the high hydrogen gaspressure provided by the compressor, and appropriate control of thesolenoid hydrogen valves 210, 212 and 214, 216 provide the continualpressure on the hydraulic fluid within the chambers 200, 202 to drive ahydraulic motor. The hydraulic fluid is in fluid communication with thehydraulic motor 280 by means of a set of pipes 222, 224, and hydraulicvalves 232, 234, 236, 238 control the flow of the hydraulic fluid, inconjunction with the hydrogen valves 210, 212 and 214, 216, to drive themotor 280. The motor 280 in turn drives one or more shafts 282 connectedto an electrical generator 284 that then produces electrical power thatis drawn off through lead wires 50, 52.

The electrical power can then be utilized in a desired manner, forexample, directly running any type of electrical device, or providingpower to a shared power grid or by storing the power in an electricalstorage device, such as a battery, or for the electrolysis of water,thus making hydrogen and oxygen in gaseous form. If electricity derivedfrom the hydride heat engine output is used to electrolyze water toproduce hydrogen and oxygen gas, then the hydrogen gas generated can bethermo-chemically reacted with carbon dioxide gas to produce carbonmonoxide gas and water via the well known reaction shown in (1) below.CO₂+H₂>CO+H₂O  (1)

Once the carbon dioxide has been converted into carbon monoxide, then amodified Fischer-Tropsch process can be employed to react the hydrogengas with the carbon monoxide gas in the presence of metal catalysts andmetal oxide catalysts under conditions of heat and temperature toproduce gaseous and liquid type fuels via the reaction (2) below.CO+2H₂>—CH₂-(Chain)+H₂O  (2)

The delta heat of formation of this reaction is about −165 kJ/mol, andthe heat can be generated by the same heat source that provides theenergy for the hydrogen compression can also produce the heart sourcefor the electrolysis reaction. For example, if a solar source of lowgrade heat is utilized, the same source can be provided to theFischer-Tropsch reaction as a self-sustaining heat source.

The chain of carbohydrate molecules can be as long as desired forobtaining the desired liquid or gaseous form of fuel and or otherprecursor uses. Some examples, without limitation, of the gaseous fuelsthat can be made using the Fischer-Tropsch reaction are methane,propane, butane, iso-propane, and others. Some examples of liquid typefuels that can be made in this using the reaction are ethanol, methanol,gasoline, diesel, kerosene and jet type fuels etc.

The catalytic metals and metal oxides that are available for use in theFischer-Tropsch thermo-chemical reactions are any of the following:nickel, nickel oxide, copper, copper oxide, iron, iron oxide, chromium,chromium oxide, vanadium, vanadium oxide, platinum, palladium, silver,silver oxide, manganese, manganese oxide, cobalt, cobalt oxide,titanium, titanium oxide, zirconium, zirconium oxide and others.

FIG. 7 is an overall process flow diagram showing the various processesdescribed proceeding form the collection of solar energy in the form ofrays from the sun until the thermo-chemical reactions are completed toproduce gaseous and liquid fuels. Solar thermal energy provides all theenergy used for the generation of electric power, hydrogen and oxygengas, CO₂ extraction from the ambient air and the production ofcarbon-neutral liquid fuels. None of the processes generate any netamounts of CO₂ or any other un-desirable greenhouse gases in the courseof the liquid or gaseous fuel synthesis. The only “waste product” mightbe considered to be water vapor, but it is also possible to recover anywaste by-product such as water and also to use it as a feed stock forthe water electrolysis hydrogen generation process.

It is also contemplated that any additional water that may be needed forhydrogen gas generation can be extracted from the ambient air in muchthe same way the CO₂ will be cooled, liquefied and then extracted.Therefore, solar plants utilizing the teachings of the present inventioncan be totally self sufficient, and are even anticipated to be able toproduce excess liquid water that can be used to grow useful crops (viahydroponics) under the solar collectors themselves.

Referring now to FIG. 7, a flow chart diagram 700 of the processes isshown, starting with the solar collector or solar thermal hot waterheater 300, also shown in cross-section in FIG. 6. The solar thermal hotwater heater 300 provides a source of low-grade hot water. The low-gradesolar thermal collector 300 provides a simple conversion of solarradiation into low-grade heat (hot water) to a temperature of betweenabout 85° C. and 100° C. Using solar energy in this way is economicaland the conversion of solar radiation energy into thermal (hot water)energy is better than 85% at 85° C. The cost can be as low as $0.03 perwatt (thermal) of installed power, most of the cost after the initialinstallation being in the maintenance of the equipment.

The thermal energy generated by the collector 300 can be used to makeelectricity in a heat engine, such as in, or similar to, the one earlierdescribed in the aforementioned '639 application. Alternatively, it canbe used to facilitate space heating and air conditioning and/orthermodynamic reactions directly. Also, as shown by the broken lines inFIG. 7, an alternative source of hot water may be found in industrialwaste heat 380 from an industrial or utility plant where the heat isotherwise let off into the environment, but can be can be retrieved.

Once the solar thermal energy has been collected by the solar waterheater 300, it is sent out to the hydride compressor 60 and the hydrogenunder high pressure can be used to power an electrical generator 30, allas is described above in relation to FIG. 1. The electricity generatedby the generator a 30 is utilized to power a CO₂ Extraction unit 720,which may utilize the hydride cooling capacity of the cold or desorbingchambers 62A or 62B (FIGS. 2A, 2B and 4), as shown by the connectiontherebetween. The carbon dioxide extraction unit 720 may extract carbondioxide from ambient air, thereby reducing the amount of carbon in theatmosphere. It is then sent to a converter unit 724, which reduces thecarbon dioxide into a form ready for the Fischer-Tropsch process, thatis, into a carbon monoxide (CO) and carbon dioxide mixture, utilizableto in the process.

The electricity generated by the generator 30 also goes to the otherportion of the system, that is, to the electrolyzer 730 which utilizesthe electricity 731 to combine with a source of water 732 to electrolyzethe water in a known electrolysis process, thereby to produce a streamof hydrogen gas 734 and oxygen 736. The oxygen can be vented to theatmosphere as a waste product as shown, or can be reintroduced into aseparate fuel cell (not shown) to produce electricity in a separateprocess, when needed. On the other hand, the hydrogen stream 734 isutilized further in the Fischer-Tropsch synthesis 740, to which it isdirected by appropriate piping.

The flow diagram of FIG. 7 also utilizes CO or a CO—CO₂ mixture that isobtained either from the CO₂ to CO converter 720, or from a stackeffluent 726 of a hydrocarbon sequestration device that is available andbeing used in some utility and conventional power generator devices. TheCO—CO₂ mixture is also combined with hydrogen derived from theelectrolyzer 730, and by possible input of either waste from anindustrial waste heat source 380 or solar generated hot water from thesolar collector 300, or heat that is generated by electricity taken formthe generator 30. The elements required for a the Fischer-Tropschsynthesis are all available in an appropriate reactor vessel 740, and byknown process parameters, desired forms of hydrocarbon a compound orcompounds are drawn off and recovered in a product recovery step in, forexample, a refining vessel 750, or alternatively, sent to a liquid fuelcollector 760 for further processing as a transportation fuel such asgasoline, diesel or jet fuels.

Any tail gas or gaseous fuels may be utilized for appropriate purposes,for example, in power generation 770 or if the recovered gas is hydrogen772, it can be used in further process steps, as shown. Furtherprocessing of any wax or heavy tar by products can utilize the hydrogento form the compounds into solid hydrocarbons, such as waxes, etc. in awax hydrocracking process 780, which if any liquid fuels result asby-products, can be utilized in the liquid fuel collection 760.Alternatively, the hydrogen that is recovered in the hydrogen recovery772 may be reused by introducing it into the hydrogen stream 734 anddiverting to the FT synthesis process 740.

Process flow diagram 700 shows one possible hydride liquefaction process720 that could be used to economically extract the carbon dioxide fromthe ambient air, and it should be recognized that the CO or a CO—CO₂mixture may be obtained by other means, for example, as a by-product ofother industrial processes. However, it should be noted that theinventive process 700 requires only low grade heat to perform the carbondioxide extraction, which can be supplied from solar energy 300 and/orwaste heat sources 380.

FIG. 8 is a simplified diagram 800 of solar energy to fuel flow of apreferred process described above for FIG. 7. The efficiency conversionof each thermodynamic step involved in the conversion of solar radiationinto electricity when a hydride heat engine conversion device is used asthe heat to work converter is described above.

Using solar energy 810 in this way is an economical way to utilize solarenergy as the conversion of solar radiation energy into thermal (hotwater) energy is theoretically better than 85% at 85° C. Other portionsof the process and system, for example, the electric power generator andshown in FIG. 5, are also a very low cost enterprise, the mostsignificant cost being that of the solar collectors and the heat enginecomponents. It is considered that to enable electric power generation inthis way, the cost may be reduced to about $0.01 per kwh in directelectric power. This electric power can be used on site, sold to thegrid, or can be used to electrolyze water to make hydrogen and oxygengas, as previously described in the aforementioned applicants. The solarheated hot water is converted into high pressure gas energy, which isthen passed through a turbine to extract usable shaft power, which inturn is used to produce electric power by turning an electric generatoras described above in FIG. 5 relative to the power generator 30.

Referring again to FIG. 8, the hot water collector provides amulti-stage hydrogen pressurizing mechanism, comprising the hydridecompressor 60, which directs the high pressure hydrogen to a heatexchanger 820 which when the hydrogen is decompressed, provides coolingto a cooling vessel 822, where air is cooled to the appropriateseparation temperature. Low pressure hydrogen is then returned to thehydride compressor 60 in a continual process. The ambient cooled air isthen processed in the cooling vessel 822 to extract the CO₂ in a cooledliquid form. Optionally, to reduce energy costs, Series counter flowheat exchangers 830 are used to start the cooling process of ambient airon it way into the cooling vessel 822, and the cool ambient air, withoutthe carbon dioxide is passed thorough the exchangers 830 so as to beginthe cooling process of the incoming air, and also to warm up theoutgoing air before it is vented to the ambient environment, as shown.

The electric power produced from a solar heat engine can be used toelectrolyze water to produce hydrogen and oxygen gas. Since waterelectrolysis is a well understood and established technology, the use ofcurrent electrolysis equipment to produce the hydrogen gas can bereduced to a cost near $1 per kg of hydrogen.

The hydride thermal compression technology used in the heat engine canalso be used to generate very low temperature refrigeration andliquefaction through the expansion of the compressed gas via known JouleThompson expansion processes in an efficient method to provide liquefiedair first, and a means for separation of carbon dioxide after. The coldtemperatures generated in this process will be used to liquefy the CO₂directly out of the cold or liquid ambient air. After the CO₂ has beenextracted from the air, the cold air will enter a counter flow heatexchanger where it will pre-cool the incoming (CO₂ containing) warmambient air, thus greatly increasing the efficiency of this process. CO₂“production” by this method is expected to cost less than $0.10 per kgof CO₂ extracted.

The generation of hydrogen gas via water electrolysis, and theextraction of CO₂ via liquefaction from air enable the production ofliquid fuels via the known Fischer-Tropsch process. Initially, CO₂ isconverted to CO using appropriate catalysts and heat. The CO then reactswith hydrogen in known reaction to make liquid fuels such as methanoland ethanol. By using the right catalyst almost any liquid fuel,including diesel, gasoline and jet fuels, can be produced by theprocess, when it is modified to provide the best reaction vehicle toobtain the desired fuels. Production of liquid jet fuels in this manneris expected to cost less than $2 per 100 k Btus of product fuel energy,and possibly as low as $1 per 100 k Btus. A most significant feature ofthe present invention, of course, is that it may be totally powered bysolar energy, as it is converted into pressurized gas and electricity,without ever relying on any outside sources. In the process described,solar thermal energy provides all the energy used for the generation ofelectric power, hydrogen and oxygen gas, CO₂ extraction from the ambientair and the production of carbon-neutral liquid fuels. None of theprocesses generate any net amounts of CO₂ or any other un-desirablegreenhouse gases.

The only “waste product” might be considered to be water vapor, but theplan is to recover that also and use it as a feed stock for the waterelectrolysis hydrogen generation process. It is also anticipated thatany additional water needed for hydrogen generation can be extractedfrom the ambient air in much the same way the CO₂ will be cooled,liquefied and then extracted. Therefore, these solar plants will betotally self sufficient, and are even anticipated to be able to produceexcess liquid water that can be used to grow useful crops (viahydroponics) under the solar collectors themselves.

It is further anticipates that using a further variation of theFischer-Tropsch process can generate waxes, tars and even solidcarbon-hydrogen “fuels” that will permanently sequester the carbon theycontain (which CO₂ was originally removed from the ambient air). Thesesolid fuels can be buried in the ground, or made into pavement,resulting in a net removal of CO₂ from the ambient air, and thus providea start to the reversal of the global warming processes that areaffecting the present environment.

The invention has been described in connection with preferredembodiments. It will be understood that modifications may be made to theinvention while retaining the general scope and teaching of theinvention herein. For example, while a solar energy collector 12 hasbeen described as providing the source of hot water for use in drivingthe multi-stage hydride compressor 60, it is possible to drive thecompressor with another type of heat source, or even a source of heatthat otherwise is expelled or vented to the environment. For example,such a heat source may operate in pipes that are embedded in a mediumthat heats up naturally for portions of the day, but may produce wasteheat that is otherwise not used for any productive purpose. Such pipesmay be embedded in, for example, an asphalt driveway, or may be arrayedon the roof of a building within asphalt shingles configured for thepurpose. Alternatively, hot water heating panels may be arrayed so as toprovide shade and thereby avoiding heating up the roof. Other types ofwaste heat sources may be used to recapture the waste heat that wouldotherwise be dissipated into the environment and transfer the heatenergy into energy, for example, electrical power, that may beimmediately used as needed or that may be stored for later use, forexample, in hydrogen storage vessels commercially available form HERAUSA, Inc. of Ringwood, N.J., USA.

Thus, the invention illustrated and described in the above embodimentsis thus understood to be for exemplary purposes only, and is not to belimited by the examples of the embodiments shown and described therein,but the invention is to be limited only by the elements and limitationsrecited in the following claims and their equivalents.

What is claimed is:
 1. A system for conversion of electrical energy intogaseous and liquid fuels, comprising: a) a collector of carbon dioxidegas from a carbon dioxide gas source; b) a reducing device for reducingat least a portion of the collected carbon dioxide gas to carbonmonoxide; c) a hydrogen producing device for providing hydrogenavailable from a hydrogen source; d) a vessel for thermo-chemicallyreacting the hydrogen gas with carbon dioxide in a Fischer-Tropschprocess in the presence of a catalyst and heat, thereby to provide ahydrocarbon fuel, wherein the collector for collecting carbon dioxidegas further comprises a cooling vessel in association with a heatexchanger that removes heat when high pressure hydrogen isdepressurized.
 2. A system for conversion of electrical energy intogaseous and liquid fuels according to claim 1 wherein the device forproducing hydrogen further comprises an electrolyzer.